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Dolphin Watch
Dolphins share food at sea
By ANN WEAVER
Article published on Thursday, Oct. 18, 2007 |
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![[Image]](/content_images/101807_out-01.jpg) |
| Photo by ANN WEAVER |
| One bull bottlenose dolphin hands the fish off to another bull, takes a share and gives it back. |
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What really got me was that the dolphins traded a fish back and forth in a reciprocal hand-off.
For humans, friends mean food. Gentlemen, when you’re wooing, how often do you take her out to eat? Ladies, when you’re giving a party, how important is planning the food? Spontaneous get-togethers become ‘let’s get something to eat.’ Without restaurants, there’d be few first dates.
Why do the best parties end up in the kitchen? Maybe it’s an ancient throwback to when good times really did mean gathering around the campfire to share whatever was sizzling among the embers.
Even if its just good manners, sharing food with friends is a basic human behavior. Don’t we fan the flickers of growing friendship by offering food or taking the food we’re offered?
Being so familiar, the significance of food sharing is easy to overlook. Can animals give us a different perspective? Absolutely. Food sharing is rare in the animal kingdom.
Most animals pugnaciously do not share their food. It’s the basis of “survival of the fittest.” That’s why you shouldn’t feed a group of wild animals. It makes them fight.
The main time animals are released from this survivalist strategy is when birds and mammals become parents. Under the humbling forces of hormones, animal parents knock themselves out to get Junior enough to eat.
When it comes to sharing food, humans are nearly unique. But when animals do share food, its as tantalizing to the social scientist as chocolates to a woman.
The hot seas of summer had cooled 10 refreshing degrees. One such pleasant day, bottlenose bull BB suddenly cruised across the bow of my boat. He surfaced ahead, returning to his hunt. Female DD1 hunted nearby. Bull DD2 hunted in the distance. They searched in earnest, rarely visible. I idled under cloudy skies.
Off the wake of a passing boat, DD2 surfaced with a large fish in his mouth and starting throwing it around. Sometimes he dropped back on his head, chucking the fish a foot or so behind him. Sometimes he whipped his head sideways, zinging the fish several feet (always to the right).
Then he floated with the fish in his mouth. The waters around him were calm. If he wrestled off bite size pieces to swallow, it wasn’t obvious.
Galvanized, BB and DD1 headed over. This was unprecedented.
DD1 swung past, chuffing and kept going. Chuffs are vocalizations that mean many things, so it’s hard to know what she was saying.
In contrast, BB approached his pal directly. They passed close together but in the opposite directions. This is the behavior you’d expect if DD2 was using the survivalist strategy of ‘my fish.’
Instead, he did a tight U-turn, released the fish near BB and floated. BB lifted his face out of the water, rested his chin on the fish and then took it in his mouth. It was the first hand-off. No scurry. No flurry.
Then they did the same thing again but changed places.
BB lifted the fish, now faceless, out of the water. He lay at the surface, mouthing it. After a time, DD2 swung around and swam alongside BB. Belly to the sky, he passed BB slowly. Pictures show his left pectoral (arm) fin against BB’s side. Then he submerged with the effortless dolphin command of swimming.
After a pause, BB submerged. It was the second hand-off.
When they reappeared, they again did the same thing and again changed places. DD2 had the fish again. This time he floated on his left side, raising the fish in his mouth over the surface. Pictures show only part of it so I don’t know if BB had taken a bite. BB swam alongside DD2, belly to the sky. His arch was stronger. If the inverted position is some kind of invitational or begging behavior, his was a greater request.
They submerged. When they re-emerged, the fish was gone. Presumably they ate it. No evidence of it floated to the surface.
All this took place without a sign of tussle.
As I salivated over the pictures that documented this entire event, I mulled over the steamy topic of animal food sharing.
Among primates, moms mostly “share” food when they let their infants snack on the crumbs that fall on their bodies. But one capuchin monkey mother I studied at Emory University in Frans de Waal’s lab gave her biscuit to her upset infant, which quieted him down (www.emory.edu/LIVING_LINKS).
In years of studying captive bonobos (pygmy chimps), I only saw unquestionable food sharing twice: mother Loretta gave her son Erin a nugget of apple when he was teething and later, when he had all his teeth, a wad of grass she chewed up for him first.
These highly significant events are rare. Are they real? de Waal showed experimentally that captive capuchins and common chimps have a sense of sharing. For example, at a pile of food, chimps are most tolerant of other chimps who groomed them earlier that day. (Grooming is social currency like money).
So the rare but significant events I’ve shared here merit scientific consideration and experimental follow-through.
Free-ranging common chimps share food too. Not only do nut-cracking mothers let their infants take nuts from their mouths. Males in successful hunting parties share monkey meat but, intriguingly, mainly with “dating” females.
If chimp behavior says anything about dolphin behavior, it’s notable that the snorting female left before the bulls shared the fish.
I leave you with a tempting tidbit. Consider that quiet coolness you feel when someone refuses the food you offer.
Dr. Weaver studies wild dolphins under federal permit GA1088-1815, National Oceanic and Atmospheric Administration. Send her an e-mail at acweaver@tampabay.rr.com or visit www.dazzlingdolphins.com.
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Article published on Thursday, Oct. 18, 2007
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